Paper winding mechanism for recording instruments



y 11951 J. E. BEVINS ET AL 2,551,866

PAPER WINDING MECHANISM FOR RECORDING INSTRUMENTS 3 Sheets-Sheet 1 Filed April 16, 1945 5Q 3 E9 Eda 51.35 .1 an E IN V EN TORX Jul/Les E. Bevias y Robert! W Hyde.

May 8, 1951 J. E. BEVINS ET AL 2,551,866

PAPER WINDING MECHANISM FOR RECORDING INSTRUMENTS y 1951 J. E. BEVINS ET AL 2,551,866

PAPER WINDING MECHANISM FOR RECORDING INSTRUMENTS Filed April 16, 1945 3 Sheets-Sheet 5 a x 56 5e v 7 J4 l X 5:. J "@1 71 E 1 55 Jlllll Q I I I 116 1/5 2i i i' r;

44 v O 'Jnveni'ors James E. Bevilcs Robert Wiiyde.

'5 ATTORNEY Patented May 8, 1951 UNITED STATES TENT OFFICE PAPER WINDING MECHANISM FOR RECORDING INSTRUMENTS of Delaware Application April 16, 1945, Serial No. 588,600

Claims.

The invention relates generally to strip chart recording and/or indicating instruments, and more particularly to a novel chart winding mechanism therefor.

The present application has been divided and copending applications Serial Nos. 149,926 and 149,927 were filed on March 13, 1950.

The main object of the present invention is to provide novel chart re-roll mechanism for the used portion of the chart.

The invention contemplates a strip chart recorder having a chart drivin roller for positively driving the chart at a substantially constant rate, and a re-roller in frictional engagement with a re-rolled portion of the chart and driven at a higher speed than the speed of the driving roller. A resiliently constrained arcuate clip encompasses to a large degree the re-rolled portion of the chart in cylindrical form and maintains the chart in frictional engagement with the re-roller. A tear-off bar may be provided between the roller and re-rollers to form a chute to the clips for the chart portion between the rollers and re-rollers. Also, an irreversible clutch may be provided for manually advancing the driving roller at a speed greater than its normal driving speed.

The foregoing and other objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawings wherein one embodiment of the invention is illustrated. It is to be expressly understood, however, that the drawings are for the purposes of illustration and description only, and are not to be construed as defining the limits of the invention.

In the drawings, Figure 1 is a perspective view of a novel recording instrument constructed according to the invention.

Figure 2 is a front elevation view of the instrument with the cover removed Figure 3 is an end view of the instrument partially in section.

Figure 4 is a vertical section taken approximately on the lines 44 of Figure 2; and

Figure 5 is a detailed section of an irreversible clutch in the chart drive gearing.

Referring now to the drawings for a more detailed description of the novel paper winding mechanism of the present invention, the mechanism is shown in Figure 1 as incorporated in a recording instrument having a casing 30 with a cover 3| which hooks to the bottom of the casing and is secured at the top of the casin by latches 32. The cover has a window 34 for viewing a plurality of fixed scales 33 and a section of a movable strip chart 35 on which is recorded values of the function being measured for a predetermined time interval. An index 36 for each scale 33 is mounted on a cord 82 on pulleys Ill (Fig. 2) and is moved by any suitable means lengthwise of the associated scale and transversely of the chart in response to a variable and indicates by lines 3? (Fig. 1) on the chart the instantaneous value of the variable. Marginal lines 38 (only one being visible in Figure 1) are recorded continuously to provide a reference independent of temperatureor humidity effects on the chart. A reference mark 39 centrally of the chart is recorded when the operator presses a reference marker button 4|.

As shown in Figures 2, 3 and 4, a driving motor 55 at the upper portion of the instrument is connected by way of suitable gearing 46 with escapeinent differential mechanism 41 carried by a framework 418 to maintain the motor speed con stant.

A multi-color inked ribbon A9 to the rear of scales 33 is Wound on a pair of spaced parallel spools 5i driven by motor 45 through gearing it in one direction or the other relative to the strip chart. A horizontal rotatable cross-shaft '52 mounts gears 35 and 53? at its ends which cooperate with gears 338 and l3 drivingly connected to spools 59. A cam 53 effects periodic reversal of the ribbon by actuating a pivoted lever 54 to shift shaft 5?. so that gear 136 engages gear Q38 or so that gear 53? engages gear I 39.

A platen 67 is secured to rods 89 slidable in hearings in framework 23. Springs 68, coaxial with rods 43$, bias the platen toward the chart. A cross-shaft 7i, rotatable on framework 48, has a pair of levers 89 depending therefrom and engaging platen 6?. A lever 12 at one end of cross-shaft 'ii is operated periodically by a timing cam '53 driven by motor 35. Platen 6'! reciprocates to and away from the chart by operation of cam 13. The mechanism described briefly above is described and claimed in the above divisional applications.

The novel paper winding mechanism includes a chart feed roll A l (Figs. 2 and 4) mounted on a stud H2 fixed in framework 48. A friction drag at the opposite end of the roll comprises a spring M3 engaging a grooved hub H4 which turns with the chart feed roll. The hub is rotatable on a lever H5 pivoted on a pin H6 attached to framework 48. A tension spring I ll biases lever 555 against a stop lit of framework 48. A screw adjustment H9 on the framework provides for positioning the paper feed roll horizontally. The strip chart passes upwardly over an idler roller l2! rotatable on framework 48 and is threaded between ribbon 49 and platen 61, and then around a chart drive roller 56 rotatable on the framework 48. Roller I2I preferably is shorter than the width of the chart and is located centrally thereof. Chart driving roller 56 includes a shaft I23 rotatably supported by framework 48 and mounting a hub I24 fixed near one end of the shaft and a plurality of hubs I25 spaced lengthwise of the shaft. The opposite end of roller 56 has a hub I33 slidable axially on shaft I23 to accommodate changes in the width of the chart. The hub is restrained against rotation of shaft I23 by a pin I34 received in a slot I32 in hub I33. Hubs I24 and I33 have a plurality of chart engaging pins I22 received in spaced openings in the chart for driving the chart. Shaft I23 is driven at a constant speed by gearing 46 which includes an irreversible slip clutch generally designated by the reference character I6. The clutch permits the chart driving roller 56 to be turned in one direction only and at a speed greater than its normal driving speed, the drive being overpowered by manual operation of a knob 15 at the opposite end of the roller.

Shaft I23 is connected by gear 45' with a hub I21 (Figure of the slip clutch I6. Springs I28 are connected to a clutch gear IZia and coact with notches I29 formed in the face of hub I21 adjacent the gear so that the springs exert a frictional effect during part of a revolution of gear I2Ia and act as pawls in cooperating with notches I29. Gear I3I connects shaft I23 with friction re-rollers 59 (Figs. 2 and 4) so that when shaft I23 is turned either manually by knob 75 or by motor 45, roller 56 and re-roilers 59 are rotated. Spring guides or clips 59 secured to framework 48 by levers I30 guide and hold the chart in a roll while it is being re-rolled by re-rollers 59. To the rear of drive roller 53 is a tear-off bar or strip 5'1 (Fig. 4) secured to framework 48 and a guide plate 57a Which c0- operates with the tear-oif bar and forms a chute to clips 58 for the strip. The chart passes from drive roller 56 through the chute formed by tearoff bar 51 and guide plate 51a and is rolled within clips 58 as the outer circumference of the roll frictionally engages re-rollers 59.

Although but one embodiment of the invention has been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the design and arrangement of the parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

We claim:

1. In a strip chart recorder having a chart driving roller for normally positively driving the chart at a substantially constant rate, the combination with said roller of a re-roller in frictional engagement with a re-ro1led portion of the chart and driven at a higher speed than that of said driving roller, and two resiliently constrained arcuate clips encompassing to a large degree the re-rolled portion of the chart in a cylindrical form and maintaining the same in frictional engagement with said re-roller.

2. In a strip chart recorder having a chart driving roller for normally positively driving the chart at a substantially constant rate, the combination with said roller of a plurality of spaced re-rollers in frictional engagement with a rerolled portion of the chart and driven in the same direction at a speed higher than that of said driving roller, and two resiliently constrained arcuate clips encompassing to a large degree the re-rolled portion of the chart in a cylindrical form and maintaining the same in frictional contact with said re-roller.

3. In a strip chart recorder having a chart driving roller for normally positively driving the chart at a substantially constant rate, the combination with said roller of a re-roller in frictional engagement with a re-rolled portion of the chart and driven at a higher speed than that of said driving roller, two resiliently constrained arcuate clips encompassing to a large degree the re-rolled portion of the chart in a cylindrical form and maintaining the same in frictional contact with said re-roller, and a tear-off bar between said rollers forming a chute to said clips for said chart portion therebetween.

4. In a strip chart recorder having a chart driving roller for normally positively driving the chart at a substantially constant rate, the combination with said roller of a re-roller in frictional engagement with a re-rolled portion of the chart and driven at a speed different from that of said driving roller, two resiliently constrained arcuate clips encompassing to a large degree the re-rolled portion of the chart in a cylindrical form and maintaining the same in frictional contact with said re-roller, and means comprising an irreversible clutch for manually advancing said driving roller at a speed greater than its normal driving speed.

5. In a strip chart recorder having a chart driving roller for normall positively driving the chart at a substantially constant rate, the combination with said roller of two spaced re-rollers in frictional engagement with the re-rolled portion of the chart and driven in the same direction at a speed higher than that of said driving roller, a lever, and two resiliently constrained clips on said lever encompassing to a greater degree the re-rolled portion of the chart in a cylindrical form and maintaining the same in frictional engagement with said re-rollers.

JAMES E. BEVINS. ROBERT W. HYDE.

REFERENCES CITED The following references are of record in the file of this patent:

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